-Original-

Pediatric Dual-Energy X-Ray Absorptiometry in Japan: A Proposal for Shared Access to Equipment

Toru Igarashi¹, Syuji Takei², Eriko Tanaka³, Utako Kaneko⁴, Tomohiro Kubota², Keisuke Okamoto⁵, Shiro Ohshima⁶ and Masaaki Mori⁷

¹Department of Pediatrics, Nippon Medical School, Tokyo, Japan
²Department of Pediatrics, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
³Department of Pediatrics, Kyorin University School of Medicine, Tokyo, Japan
⁴Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
⁵Department of Pediatrics and Developmental Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
⁶Department of Rheumatology, National Hospital Organization, Osaka-Minami Medical Center, Osaka, Japan
⁷Department of Lifetime Clinical Immunology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan

Background: Regular assessment of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) is essential for detecting glucocorticoid-induced osteoporosis in juvenile-onset autoimmune diseases. Z-score is used to standardize osteoporosis assessment in children and is evaluated with only one of three devices in Japan. The purpose of this study was to determine how many Japanese medical facilities for pediatric rheumatic diseases were unable to use Z-scores to evaluate osteoporosis.
Methods: Electronic questionnaires were distributed between 2017 and 2019 to hospitals belonging to the Pediatric Rheumatology Association of Japan and to university hospitals and public children's hospitals that provide medical care for pediatric rheumatic diseases. The questionnaire inquired about the location of DXA measurement, manufacturer (Hologic, GE healthcare, Hitachi), and measurement site, and the answers were collected using Google Forms. Statcel 4 was used for analysis.
Results: Overall, 120 facilities responded to the survey, of which 117 had DXA. In the remaining three facilities, DXA was not installed in two and was out of order in one. Bone loss in childhood was evaluated using a Z-score calculated from age-based reference values; however, 30% of hospitals without HOLOGIC DXA could not evaluate osteoporosis by Z-score in Japanese childhood. The characteristics of the hospitals enrolled in this study did not bias the selection of Hologic DXA.
Conclusions: Neighboring institutions should consider sharing access to Hologic DXA equipment, to ensure use of uniform reference values. GE BMD reference values should be established for Japanese children.

J Nippon Med Sch 2021; 88: 296-300

Keywords
dual-energy X-ray absorptiometry, corticosteroid, osteoporosis, systemic lupus erythematosus

Correspondence to
Toru Igarashi, Department of Pediatrics, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
iga@nms.ac.jp

Received, April 24, 2020
Accepted, July 31, 2020